Noise vibration damping for sewing machines



April 28, 19 59 C. o. KISHIBAY NOISE VIBRATION DAMPING FOR SEWING MACHINES Filed May 24, 1955 3 Sheets-Sheet l ,r:::::::::i- ::::l

INVENTOR Charles 0. Kishibay BY 2 4 (i ATTORNEY April 28, 1959 c. o. KISHIBAY NOISE VIBRATION DAMPING FCR SEWING MACHINES Filed May 24, 1955' 3 Sheets-Sheet 2 INVENTOR Charles 0. Kishibay ATTORNEY WITNESS WM k/m c. o. KISHIBAY 2,883,955

3 Sheets-Sheet 3 INVENTOR Charles 0. Kishibay Fig.5

A ril 28, 1959 NOISE VIBRATION DAMPING FOR SEWING MACHINES Fild May 24, 1955 Fig.4

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WITNESS NOISE VIBRATION DAMPENG FOR SEWING MACHINES Charles 0. Kishihay, Trumbull, Conn, assignor to The inger Manufacturing Company, Elizabeth, 'N..i., a corporation of New Jersey Application May 24, 1955, Serial No. 510,685

6 Claims. (Cl. 112-258) This invention relates to sewing machines, and more particularly, to vibration and sound damping supports and enclosures for sewing machines.

The demands upon the skill, dexterity and attentiveness of sewing machine operators has kept pace with the constant development of sewing machines capable of attaining higher sewing speeds. The effect upon the machine operators of stress and fatigue has, by the same token, become more acute and under present day conditions constitutes an increasingly important factor as regards high productivity. In the absence of corrective measures, increased sewing speeds result in more pronounced vibration and a higher level of machine noise. The numbing effect to arms and hands of the operator from continued contact with the vibratory table or the like carrying an undarnped high speed sewing machine is extremely fatiguing as is the high noise level to which the operator is continuously subjected during operation of a machine carried in a conventional support and enclosure.

It is an object of this invention to provide a practical and eificient arrangement for damping the transmission of vibrations from a sewing machine to the support upon which the machine is carried.

Another object of this invention is to provide a sound damping bottom closure for a sewing machine.

It is an object to provide a lubricant drip pan for a sewing machine constructed and arranged to damp noise emanating from the internal moving parts of the sewing machine as well as to minimize noise resulting from vibration of the drip pan itself.

With the above and other objects and advantages as will hereinafter appear, this invention comprises the devices, combinations, and arrangements of parts hereinafter described and illustrated in the accompanying drawings of a preferred embodiment thereof in which:

Fig. 1 represents a front elevational view of a sewing machine with a portion of the frame, the machine supporting table top, and the drip pan being illustrated in vertical cross section,

Fig. 2 represents a top plan view of the installation of Fig. 1 in which the sewing machine frame is broken away clearly to illustrate the machine supporting members and the drip pan.

Fig. 3 is a cross-sectional view taken substantially along line 33 of Fig. 2,

Fig. 4 is an enlarged cross-sectional view of a machine supporting corner bracket taken substantially along line 4-4 of Pig. 2, and

Fig. 5 is an enlarged cross-sectional view of a modified form of a machine supporting corner bracket taken substantially along line 5-5 of Fig. 2.

Referring to the drawings, Fig. 1 illustrates a modern high speed sewing machine disposed in normal operating position in a cut-out 11 formed in a supporting table top 12. The sewing machine is of the type disclosed in the US. Patent of Van Wagener et al. No. 2,63 6,464, April 28, 1953, which may be referred to for a more complete 2,883,955 Patented Apr. 25, 1959 description of those parts thereof which are not directly related to the present invention. Generally, the sewing machine comprises a frame including a bed 13, a standard 14 and a bracket-arm I5. lournaled in the bracket-arm is a main drive shaft 16 carrying a driving pulley 17 from which a bed shaft 18 is driven by means of a clip belt 19. The main drive shaft 16 actuates a needle thread take-up indicated at 2% and serves to reciprocate the needle-bar 21 in the usual fashion, while the bed shaft 18 serves to actuate the work feed-dog 22 and to rotate the loop-taker which is in the form of a rotary hook 23 of the type adapted to be rotated at twice the speed of reciprocation of the needle-bar. The feeding mechanism is of the four motion variety and includes a feed-lift eccentric 24 and a feed-advance eccentric 25 each carried on the bed-shaft. The lift and the advance eccentrics are operatively connected in conventional manner so as to oscillate respectively a feed-lift rock shaft 26 and feed-advance rock shaft 27. As indicated in Fig. 3, the rock shafts 26 and 27 are operatively connected each to opposite ends of a feed bar 28 carrying the feed-dog to impart a combination of vertical and horizontal motion to the feed-dog.

The motions of the various components of the sewing machine mechanism give rise to vibration of the entire machine which if transferred directly to the machine sup porting table top would provide an undesirable work place for the machine operator. In the present invention, the vibrations of the sewing machine are effectively isolated by means of cushions of flexible material such as rubber separating the machine from the supporting table top. The cushions, moreover, are each formed and arranged so as to flex primarily in shear under'the load presented by the sewing machine.

Preferably, the cushions, indicated generally as 30, are disposed at the corners of the cut-out 11 in the table top as shown in Fig. 2. The corners of the cut-out are recessed as at 31 to accommodate the cushions and the projecting ends of angle brackets 32 bonded one to the outer edge of each cushion. The brackets 32 are apertured to receive fastening screws 3333 threaded into the table top. As shown in Figs. 4 and 5, the recesses 31 are formed with vertical side walls extending to the bottom edge of the table top so that the cushions 30 are supported solely by the brackets 32. At the top of the table top, the recesses 31 may be formed to accommodate a raised rib 34 of the cushions 30 shaped to fit the contour of the corners of the sewing machine bed as illustrated in Fig. 2 so as to cushion movements of the machine frame in a horizontal plane to prevent contact of the bed with the table top. The cushion extends inwardly from the rib 34 to provide a segment shaped shelf 35 extending beneath the corners of the sewing machine bed so as to support the weight of the machine and to cushion the vibrations in a vertical plane. Since the cushions are supported solely by the angle brackets 32, the cushions will not act simply as compression members as have been commonly employed in the prior art. Furthermore, the shelves 35 of the cushions are formed in a novel manner so as to insure that the cantilevered cushion will flex primarily in shear rather than to partake of a simple bending action. The manner in which the cushion illustrated in Fig. 4 is formed to encourage shearing action differs from that illustrated in Fig. 5. In the version illustrated in Fig. 4, a plate 36 preferably of metal or other rigid material is bonded to the inside face of the segment shaped shelf portion of the cushion. The plate 36 is disposed to extend upwardly beyond the preferably horizontal shelf surface 35 to provide a raised portion indicated as 37 in Fig. 4. The sewing machine bed, therefore, in engaging the shelf 35 must first contact the raised portion 37v of the spear- 55 plate 36. When the point is reached in which the machine bed engages the entire shelf surface 35, the material of the cushion will be flexed in shear with a maximum deflection occurring adjacent the plate 36.

In the modified form of cushion illustrated in Fig. 5, the plate 36 has been dispensed with and instead the shearing action is augmented by means of a novel configuration of the shelf 35. Rather than being formed horizontal as in the form illustrated in Fig. 4, the shelf of the modified version is inclined upwardly and inwardly to provide a raised inner edge 38. The machine bed, therefore, in engaging the shelf 35 must first contact the raised inner edge 38 and in successively engaging more of the shelf, the cushion member will be flexed primarily in shear. It has been found that a shelf inclination, shown at A in Fig. 5, of approximately provides a satisfactory shearing action.

The cushions 30 may be arranged one at each of the four corners of the machine bed. However, if a hinged connection between the machine and the table top is desired, the cushions may be omitted at the rear corners of the bed and a pair of resilient hinge pintles 49-40 substituted therefor. The hinge construction as shown in the drawings follows that disclosed in my co-pending application Serial No. 456,368, filed September id, 1954-, now Patent No. 2,829,396, granted April 8, 1958, to which reference may be had for a more complete description. It is pointed out that the hinge pintles are preferably formed of a resilient material molded about one arm 41 of a bracket member 42 which is adapted to be secured to the machine bed as by means of a pin 43 which is accommodated in a hole 4-4 formed in the rear of the bed. The free extremity of the flexible pintle member is cylindrical in form and is seated in a similarly contoured recess formed in the table top to provide a hinge for the sewing machine. The bracket-arm 41 extends as shown in Figs. 2 and 3 toward the cylindrical portion of the flexible pintle member so that in supporting the weight of the sewing machine, the pintle is flexed in shear.

Hand-in-hand with the problem of control of vibration of high speed sewing machines is the problem presented by the high noise level incident to the operation of such machines. In the present invention, damping of noise is accomplished in a highly efficient manner by the use of a drip pan of novel construction.

The use of a drip pan as an incident to the support and enclosure of a high speed sewing machine is almost universal in the art inasmuch as lubrication in one form or another is essential with these machines. The drip pan serves to protect the operator from the normal throw-off of lubricant from the moving parts of the sewing machine and in some instances may also be used as a lubricant storage reservoir.

Drip pans which have been and are on the market today are constructed of metal being formed either by die casting or as a sheet metal stamping. These prior art constructions exhibit in common a disadvantage in that they provide excellent sources as well as transmitters of sound. The present invention provides a drip pan designed to react in a highly favorable manner in damping sounds produced in either of these fashions.

Practically every moving part in the sewing machine actuating mechanism constitutes a source of sound; the take-up and needle-bar actuating linkages, the clip belt 19, the feed mechanism and the rotary hook 23 to mention but a few. The sound produced by these parts is directed immediately into a chamber formed by the machine bed together wtih the drip pan as is indicated generally at 50 in the drawings, which encloses the bottom of the sewing machine and to this end is secured to the table top as by fastening nails 5151.

In the preferred embodiment illustrated in the drawings, the drip pan is open, as at 52, adjacent the rotary book 23 in order to provide convenient access to the under stitch forming instrumentalities. It will be understood,

however, that the drip pan may be closed on all four sides if it is to be used with a sewing machine in which the under stitch forming instrumentalities are readily accessible from above. The drip pan in any event is inherently in a most favorable location to couple the sounds of the sewing machine actuating mechanism with the outside atmosphere.

Our knowledge of the coupling of sound sources to the atmosphere is, even in the field of musical sounds, mainly empirical. We know, for instance, that it takes winds of tremendous intensity to produce more than a whisper from a guy wire standing alone but that a wire, if coupled efficiently to the atmosphere, as by way of a proper sounding chamber, may fill an entire auditorium with sound on being vibrated very gently with a bow. Metal drip pans in use in the prior art exhibit a measurable drum head effect and thus prove to be efficient couplers of the sound of the sewing machine actuating mechanism with the atmosphere. In many cases, the prior art drip pans have been found actually to amplify these sounds.

In accordance with the present invention, the drip pan is fabricated so as to have a very low natural frequency, i.e., a natural frequency which approaches or is lower than that corresponding to the threshold of audibility. To this end, the drip pan is preferably made of a flexible synthetic plastic material. it has been found that the group comprising synthetic elastomers, polymers and copolymers and plasticized synthetic resins exhibit such characteristics. In particular, the polymer polyethylene has been found to serve admirably well for this purpose. A copolymer of styrene and an elastomer such as neoprene has also been found to serve well in this capacity.

Referring to Figs. 1, 2 and 3 of the drawings, the drip pan is preferably stamped or moulded in one piece and is formed with a front side wall 53, a rear side wall 54, an end wall 55 and a slightly dished bottom 56. Adjacent the top edge of the front and rear side walls a plurality of grommets 57-57 are set to strengthen the walls for accommodation of the fastening nails. The bottom 56 is formed with oil collecting grooves 5858 which converge from each corner of the bottom to form a sump 59 common to each of the grooves. The free end of the bottom 56 adjacent the rotary hook 23 is formed with a raised lip fill which serves to strengthen and stiffen the free edge. Disposed beneath a presser lifting rod 61 in the sewing machine is an upwardly projecting boss 62 formed in the bottom 56 of the drip pan. The boss 62 is apertured as at 63 to accommodate a presser-lifter connection (not shown) which may be of any conventional construction.

Another advantage gained by the use of an elastomeric synthetic plastic drip pan is that its flexibility permits limited distortion, thus enabling the drip pan to accommodate variations in the size and shape of cut-outs in sewing machine supporting table tops. Moreover, because of the flexibility of the drip pan, excess oil collected in the sump and grooves of the drip pan bottom may be drained off readily and conveniently. It is conventional in metallic drip pans to provide complicated drainage facilities as, for instance, a permanent drainage line leading to a container carried elsewhere beneath the table top. Although such an arrangement may be incorporated in a plastic drip pan if desired, with the construction of this invention drainage into any desired container may be accomplished simply by depressing one side or the other of the raised lip 60 at the free edge of the drip pan bottom portion.

In addition to being a poor coupler of sound originating elsewhere, the drip pan of the present invention is a poor source of sound. Metallic drip pans and those having high modulus of elasticity are influenced by the vibrations transmitted to them through the table top from the sewing machine. In turn, these rigid drip pans exhibit a drum head or sounding board effect, that is, they themselves produce sounds due to the vibration to which they are subjected. The low natural frequency of the drip pan of this invention practically eliminates this drum head effect. The combined result of the use of cushions flexed in shear to support the sewing machine with respect to the table top and a drip pan of elastomeric synthetic resin is to provide a machine which is quieter and smoother in operation than has heretofore been attained.

Having thus set forth the nature of the invention, what I claim herein is:

1. In combination, a sewing machine, a table top having a machine accommodating cut-out formed therein, flexible cushioning members interposed between said sewing machine and said table top, said cushioning members comprising a metallic bracket, means for fastening said bracket to said table top adjacent said cut-out, a block of flexible material bonded to said bracket and extending into said cut-out in cantilever fashion, and means for constraining said sewing machine to bear upon only the cantilevered portion of said block of flexible material, and a drip pan secured to said table top adjacent said cut-out and disposed beneath said sewing machine accommodating cut-out, said drip pan having a natural frequency of vibration lower than that corresponding to the threshold of audibility.

2. In an assembly comprising a sewing machine, a sewing machine supporting table having a machine accommodating cut-out, and a lubricant drip pan secured to said table top beneath said sewing machine, means for isolating vibration of said sewing machine from said drip pan comprising a plurality of cushioning members interposed between said sewing machine and said table top, each of said cushioning members comprising fastening means secured to said table top, a block of flexible material extending in cantilever fashion from said fastening means into said cut-out, and defining a shelf adapted to be engaged by said sewing machine, and an upwardly extending protuberance disposed at the free extremity of said block, said protuberance being arranged to insure deformation of said block primarily in shear as said protuberance and said shelf are depressed towards a common level under the weight of the sewing machine.

3. A device as set forth in claim 2 in which the protuberance at the free extremity of said block of flexible material is provided by means of a metal plate bonded thereto, said plate having an upper extremity extending above the level of said shelf.

4. A device as set forth in claim 2 in which the shelf of said block of flexible material is inclined upwardly and inwardly toward the free extremity thereof, such that the protuberance is formed of the flexible material itself.

5. In an assembly including a sewing machine, a sewing machine supporting table having a machine accommodating cut-out, means for isolating vibration of said sewing machine from said table comprising, a plurality of cushioning members interposed between said sewing machine and said table top, each of said cushioning members comprising a metallic bracket, means for fastening said bracket to said table adjacent to said cut-out, a block of flexible material arranged in engagement with said bracket and extending beyond said bracket and into said cut-out in cantilever fashion, means bonding together said engaged portions of said bracket and said block of flexible material, a top surface formed on said block of flexible material providing a sewing machine supporting shelf thereon, and means for constraining said sewing machine to bear upon only that portion of said top surface which is vertically above that part of the block which extends beyond said bracket and into said cut-out in cantilever fashion.

6. in an assembly including a sewing machine, a sewing machine supporting table having a machine accommodating cut-out, means for isolating vibration of said sewing machine from said table comprising, a plurality of cushioning members interposed between said sewing machine and said table top, each of said cushioning members comprising a metallic bracket formed with a substantially planar face, means for fastening said bracket to said table with said planar face disposed substantially vertically, a block of flexible material, a substantially planar side face formed thereon, means bonding the side face of said block of flexible material to the planar face of said bracket to support said block of flexible material in cantilever fashion defining a free extremity of said block extending from said bracket into said cut-out, a top surface formed on said block of flexible material providing a sewing machine supporting shelf thereon, said means for constraining said sewing machine to bear only the free extremity of the top surface of said block of flexible material.

References Cited in the file of this patent UNITED STATES PATENTS 1,237,680 Needle Aug. 21, 1917 1,334,088 Goldstone Mar. 16, 1920 1,961,993 Thompson June 5, 1934 2,137,021 Lum Nov. 15, 1938 2,183,366 Chason et al. Dec. 12, 1939 2,206,285 Kaier July 2, 1940 2,295,640 Cumfer Sept. 15, 1942 2,341,975 Chason Feb. 15, 1944 2,694,375 Attwood Nov. 16, 1954 2,723,637 Sauer Nov. 15, 1955 

